Rails Model find where not equal

How can I find records in my database on a not equal condition? I have this now, but is there a fancy rails-speak way of doing it?

GroupUser.where('user_id != ?',me)

Solution 1:

In Rails 4.x (See http://edgeguides.rubyonrails.org/active_record_querying.html#not-conditions)

GroupUser.where.not(user_id: me)

In Rails 3.x

GroupUser.where(GroupUser.arel_table[:user_id].not_eq(me))

To shorten the length, you could store GroupUser.arel_table in a variable or if using inside the model GroupUser itself e.g., in a scope, you can use arel_table[:user_id] instead of GroupUser.arel_table[:user_id]

_{Rails 4.0 syntax credit to @jbearden's answer}

Solution 2:

Rails 4

GroupUser.where.not(user_id: me)

Solution 3:

The only way you can get it fancier is with MetaWhere.

MetaWhere has a newer cousin which is called Squeel which allows code like this:

GroupUser.where{user_id != me}

It goes without saying, that if this is the only refactor you are going to make, it is not worth using a gem and I would just stick with what you got. Squeel is useful in situations where you have many complex queries interacting with Ruby code.

Solution 4:

Rails 4:

If you want to use both not equal and equal, you can use:

user_id = 4
group_id = 27
GroupUser.where(group_id: group_id).where.not(user_id: user_id)

If you want to use a variety of operators (ie. >, <), at some point you may want to switch notations to the following:

GroupUser.where("group_id > ? AND user_id != ?", group_id, user_id)